The answer here is (believe it or not): "it depends".
My Rex45 PM2 still looks like the day I bought it, as do my M4 and 52100 and all of my other such knives.
I don't go out of my way to oil them on a weekly schedule. In fact I don't actually do anything. Maybe I get a greasy finger now and then and rub some of it on one of these knives. I am way too lazy and undisciplined to be compulsive about maintaining fussy knives. Maybe if I had had some heartbreak experience with finding a beloved knife all rusted to utter ruin I might change my ways. Even one little orange pit might change my ways. So far though, all is well here in cactus city.
My knives are in a rotation of sorts, so it isn't like any one of these is seeing a lot of pocket time. Some people sweat more than I do, and/or have sweat with a really corrosive chemistry, or so they will have you believe.
What I am saying is to not let corrosion worries keep you away from a steel like Rex45. Unless you live in Mobile, Alabama. I know a guy from Mobile and he tells me the most humid day in Tucson is dryer than the driest day in Mobile. So it depends, but don't freak out.